text: extern int nd ();
  int main () {
    int i,x,y,offset_x,offset_y;
    x=0;
    y=0;
    for (i=0; i < nd (); i++){
      offset_x = nd ();
      offset_x += i+4;
  
      offset_y = nd ();
      offset_y += i+4;
  
      x+=offset_x;
      y+=offset_y;
    }
    return 42;
  }
  